Epithelial salivary gland tumors in two distant geographical locations, Finland (Helsinki and Oulu) and Israel (Tel Aviv): a 10-year retrospective comparative study of 2,218 cases.

Salivary gland tumors (SGTs) of epithelial origin are relatively rare, and worldwide reports show considerable variations in their epidemiology. The aim of this study was to examine, for the first time, the records of SGTs from two very distant geographical locations, Finland (two medical centers) and Israel (one medical center) between 1999 and 2008, based exclusively on the 2005 WHO classification of head and neck tumors, and to compare those data to the other available (single-center) studies that used the same classification. A total of 2,218 benign and malignant tumors diagnosed in the three centers were analyzed. Differences in classification of the tumors were found between the two geographical locations as well as between the two centers from Finland. There was a higher ratio of benign-to-malignant SGTs in the Finnish centers (5.4:1 and 7:1) compared to the Israeli center (2:1), a higher frequency of tumors of minor salivary glands in the Israeli center (34%) than in the Finnish centers (4 and 11%), and a higher frequency of malignant SGTs in the minor salivary glands in Israel (64.5%) than in Finland (10.9 and 27%). The diversity of these multicenter data are compatible with reports from different parts of the world. We conclude that conducting epidemiologic surveys based on the latest WHO classification provides clinicopathologic correlations on SGTs that seem to be characteristic even in small geographical regions.